Process for oxidation



Nov. 5, 1946. )Aj FARKAs ErAL I PROCESS FO OXIIDATION Filed Aug. 16, 1943 WLOQS SQQLQUDAU Patented Nov. 5, v1946 UNITED STATES) PATENT ori-fics* Paocnss Foa OXIDATION Adalbert Farkas andmhur F. stanley, Jr., Lang Beach, Calif., asslgnors to Union (lilCompanyof California, Los Angeles, Calif., a corporation' of California Application August 16l 1943, Serial No. 498.775

l 13 Claims. 4(Cl. 260-593) 'his invention relates to partial oxidation prodl bon derivatives from hydrocarbons or hydrocarbon fractions, using' in this case a method which limits the extent of oxidation thereby limiting the number and complexity of oxygenated products thus allowing the more ready segregation of the oxygenated derivatives into pure compounds.

Another object of the invention is to prepare from a single hydrocarbon or from a given hydrocarbon fraction, such as a relatively narrow boiling range hydrocarbon fractionI prepared from petroleum, cyclic and/or acyclic alcohols and ketones with a minimum production of .the more highly oxidized products, such as aldehydes, acids, hydroxy acids etc., and ultimate oxidation products such as water and carbon dioxide.

A further object of the invention is to provide a method fgr producing alcohols and/or ketones.

in substantial quantities from hydrocarbons.

A further object of our invention is to prepare cyclic and/or acyclic alcohols and ketones having ve or more carbon atoms per molecule from non-aromatic cyclic hydrocarbons, whether used alone or mixed with acyclic or aromatic hydrocarbons boiling at or near the same temperature as the non-aromatic cyclic hydrocarbons, by a process involving oxidation with oxygen, air, or other oxygen-containing gas.

A particular object of our invention is to prepare a lubricating oil addition agent and to prepare a lubricating oil composition comprising a major proportion of a lubricating oil and a minor proportion of an addition agent, said addition the partial oxidation products being removed continuously by processes involving fractional distillation, extractive distillation, azeotropic 'distlllation, solvent extraction or adsorption from the slightly oxidized hydrocarbon or. hydrocarbon fraction at such a rate that only minor proportions of these primary oxidation products are further oxidized, thus permitting the production of relatively high yields oi partial oxidation products. 'v

The invention' also comprises separating the products of partial oxidation into substantially pure compounds or into fractions comprising alcohols or ketones by relatively simple processes involving physical and/or chemical treatments, the particular method employed in a, given case depending upon the character andthe complexity of the oxygenated products to be separated,

The invention further comprises converting said partial oxidation products into lubricating oil addition agents 'and blending said addition agents with lubricating oil to produce lubricating oil compositions having improved iilm strength, anticorrosion and detergency characteristics.

Alcohols and ketones having five or more carbon atoms per molecule are particularly valuable' products. The ketones are used in fthe'synthesis of chemicals and perfumes, as solvents for lacquers, gums, resins, nitrocellulose, etc., and for the production of alcohols. The alcoholshave use in perfumes, as antifoaming agents, as solvents for dyestuffs, oils, waxes, gums, resins, etc., in the production of esters, acids, etc., as emulsifying agents, and in textile inishing compositions. Also alcohols produced by our oxidation process may be reacted with phosphorus pentasulflde to form the corresponding dialkyl thiophosphates and the products of this reaction may then be reacted with metals or metal oxides to form the corresponding metallic salts of the dialkylthiophosphates and/or dicycloalkylthiophosphates and these compounds are excellent lubricating oil additives.y When blended with mineral lubricating oils in amounts in the order of from about 0.1% to about 10% or more the metal dialkyl agent being a polyvalent metal salt ofthe reacthiophosphates impart high film strength to the oil, they improve the stability of they oil toward oxidation, reduce bearing corrosion in an enginev and, when used in conjunction with other additives having detergency characteristics, ,they

markedly increase the detergency of the lubricating oil blends containing the latter additives. Such other additives, which may be employed in amounts in the order of from about 0.1%to about 5.0% of the finished lubricating oil composition,

may be oil-soluble polyvalent metal soaps of various carboxylic acids, such as phenylated carboxylic acids, e. g., calcium phenyl stearate and magnesium phenylstearate, chlorinated and phenylat- 6.0 ed atty acids, e. g., calcium dichlorophenylsteaother additives having detergency characteristics,"

include al1 mineral lubricating oils because we :dnd that the valuable characteristics of our ad'- dition agent are imparted to all mineral lubricating oils. We prefer to employ treated oils such as acid rened `Westem lubricating oils, highly solvent rened Western lubricating oils or We may use Eastern lubricating oils such as Pennsylvania oils.

' The alcohols which may be prepared by the partial oxidation of hydrocarbons and which may 'be employed to produce desirable lubricating oil additives when treated in the above manner include the cycloaliphatic alcohols containing from ilve to about twelve carbon atoms and preferably seven to ten carbon atoms per molecule and the acyclic aliphatic alcohols containing from seven to about eighteen carbon atoms and preferably eight to fourteen car-bon atoms per molecule.

'4 one of these metals to form the corresponding polyvalent metal salt of the dialkyl or dlcyclo- Y alkyl phosphates.

The lubricating 'oil additives may be prepared by heating and agltating a mixture of 4 gram moles of the alcohol with 1 gram mole of phosphorus pentasulfide at a temperature of 250 F. to 300 F. until the PzSs is completely dissolved, indicating that it has reacted completely with the alcohol and the product of this reaction is maintained at the same temperature and agitated wtih one gram mole of an oxide of one of the polyvalent metals disclosed hereinabove or with one gram atom of the polyvalent metal itself to form the metal salt of the thiophosphate ester. The first reaction results in the formation of relatively large proportions of the dialkyl or dicycloalkyl thiophosphates represented by the following formula in which R represents the hydrocarbon radical of the alcohol:

in s=ron \on It is known vthat other acid thiophosphate esters are produced by the above reaction but their pres- Phosphorus pentoxide may be used in place of the phosphorus pentasulde in the production of lubricating oil addition agents and in this case the oxyphosphate esters are formed. Thus 4 I moles of an aliphatic or cycloaliphatic alcohol may be reacted with one mole of phosphorus pentoxide to produce the corresponding dialkyl or dicycloalkyl phosphates. These phosphate esters may then be reacted with one of the above Alcohols which are useful for the above purposes are in general difficult and costly to produce, their preparation requiring the use of expensive chemical processes. We find that we may produce alcohols, both cyclic and acycllc, containing ve or more carbon atoms per molecule by a relatively inexpensive and simple proccss involving partial oxidation of certain hydrocarbons or hydrocarbon fractions, separating the products of partial oxidation from the unoxidized hydrocarbon and subsequently segregating the partial oxidation products into fractions consisting primarily of alcohols and ketones. The ketones, if desired, may be subsequently converted into the corresponding alcohols as indicated hereinbelow.

In carrying out the production of partial oxidation products according to the principles of our invention, the hydrocarbon or narrow boiling range hydrocarbon fraction to be oxidized is blown with oxygen, air, or other gas containing free oxygen until the proportion of hydrocarbon molecules oxidized is about 0.1% to about 10% or preferably about 0.5% to about 5.0% of the total molecules present and the concentration ofoxygenated molecules is thereafter maintained at an approximately constant value by continuously withdrawing portions of the slightly oxidized hydrocarbon material present in the oxidation vessel, separating the oxygenated molecules from the unoxidized hydrocarbon material, as by fractional distllation, and returning the latter material to the oxidation unit together with sufficient additional feed to maintain an approximately constant level in this vessel. The volatile materials, such as any oxygenated degradation products, pass out of the unit with spent air or other gaseous oxidizing medium. This operation involving the separation of oxidation products from unoxidized hydrocarbons can be considered to be a stripping operation.

Although we may treat any hydrocarbon or narrow boiling hydrocarbon fraction We prefer to employ a non-aromatic cyclic hydrocarbon, or a narrow boiling range hydrocarbon fraction, containing at least one non-aromatic cyclic hydrocarbon. Thus, hydrocarbons which may be used as feed include cyclopentane or any of the mono, di, tri, tetra, or pente. alkylcyclopentanes, such as methylcyclopentane, dimethylcyclopentane, methylethylcyclopentane, etc.; cyclohexane or any of the mono, di, tri, tetra, penta, or hexa alkylcyclohexanes, such as methylcyclohexane, dimethylcyclohexane, diethylcyclohexane, etc.; naphthenyl cyclopentanes or cyclohexanes containing one or more naphthenyl groups, such as bicyclopentane, bicyclohexane and alkyl substituted bicyclopentanes and bicyclohexanes, such as methylbicyclopentane and methylbicyclohexane; hydro aromatics, such as decahydronaphthalene and alkyl substituted hydroaromatics, such as methyldecahydronaphthalene. Mixtures of two or more of the above disclosed naphthene hydrocarbons may be employed as feed if desired when such mixtures have boiling ranges not wider than about 50 F. and preferably not Wider than about 10 F. Also hydrocarbon fractions containing at least one of the above disclosed naphthene hydrocarbons together with non-naphthenic hydrocarbons, such as for example, paraiiins or olefins or aromatics, or mixtures of these non-nanhour invention; lSuch fractions should have a boil- -ing range not wider ,than about 50 F. and prei'- erably notwider than about F;

' Other hydrocarbons which may desirably be treated'by our process include the cycloolenn hydrocarbons and the naphthene hydrocarbons containing oleflnie substituents,` narrow boiling range mixtures of the oleilnic cyclic hydrocarbons or narrow boiling range fractions contain- A ing one or more of these oleflnic cyclic hydrocarbons. Thus we may employ cyclopentene and cyclopentadiene and the mono, di, tri, etc., alkyl cyclopentenes and cyclopentadienes; cyclohexene and cyclohexadiene andthe mono, di, tri, etc.,

' alkyl cyclohexenes and cyclohexadienes; mixtures of these hydrocarbons when such mixtures have boiling ranges not wider than about 50 F. and preferably not wider than about 10 F.; hy-

drocarbon fractions containing one or more of the above mentioned cyclooleflns or cyclodiolefins together with one or more dissimilar hydrocarbons, such as parafilns. naphthenes, oleflns Aand aromatics; alkenyl substituted cyclopentanes and cyclohexanes, such as ethenylcyclopentane, ethenylcyclohexane, etc.; allienyl substituted mono, di, tri, etc., alkyl cyclopentanes and cyclohexanes, such as methylethenylcyclopentane, dimethylethenylcyclohexane, etc.; mixtures of such alkenyl substituted cyclopentanes, cyclohexanes, alkyl cyclopentanes and alkyl cyclohexanes; and hydrocarbon fractions containing at least one of the alkenyl derivatives, such mixtures or fractions having relatively narrow boiling ranges as specified hereinabove for mixtures or fractions may b'e employed. The methods of effecting azeotropic distillation, extractive distillation and solvent extraction and the azeotrope formers or solvents which may be employed are disclosed hereinbelow.

Alcohols and ketones which may be produced by our process include the cycloaliphatic and alkylcycloaliphatic alcohols and ketones, such as cyclopentanol and cyclohexanol, and cyclopentanone and cyclohexanone; the various isomeric methyl-, ethyl, propyl-, isopropyl-, butyl, etc., cyclopentanols, cyclohexanols, cyclopentanones and cyclohexanones; the various isomeric dimethyl, methy1ethy1-, methylpropyl, methylisopropy1, methylbutyl, diethyl, etc., cyclopentanols, cyclohexanols, cyclopentanones and cycl'ohexanones and higher molecular weight homologs of these alkylcycloaliphatic alcohols and ketones. Other products include the cyclooleflnic alcohols and ketones, such as cyclopentenol, cyclohexenol, cyclopentenone and cyclohexenone; the various mono, di, tri, etc., alkyl substituted cycloolefinic alcohols and ketones, such as for example, the various isomeric methylcyclopentenols, methylcyclohexenols, methylcyclopentenones, methylcyclohexenones and higher homologs of these compoundspthe alkenyl cycloaliphatic alcohols and ketones, such as ethenylcyclopentanol, ethenylcyclohexanol, ethenylcyclopentanone and ethenylcyclohexanone and the higher homologs of these compounds. such as the isomeric methylethenylcyclohexanols, methylethenylcyclohexanones, ethylpropenylcyclopentanol, etc. The aliphatic alcohols and ketones which may be produced by our process include pentanol, pentanone, the various isomeric methyland ethyl-pentanols and pentanones, hexanol `and hexanone, the isomeric methyl, ethyl-, propyl, and isopropylhexanols andhexanones; dialkylpentanols, pentanones, hexanols, and hexanones and higher homologs of these compounds such as trimethylhexanol, dimethylethylhexanone, etc. Oleflnic alcohols and ketones which may be produced include hexenol and hexenone; the various isomeric methyl, ethyl, etc., hexenols and hexenones; heptenol, heptenone and the various alkyl substituted heptenols and heptenones; higher molecular weight olenlc alcohols and ketones including octenol, octenone, nonenol, nonenone, decanol, decanone, and the alkyl substituted derivatives of these alcohols and ketones, such as the various isomeric methyl-octenols, methylnonenones, methyl-ethylnonenols, etc.

The above disclosed alcohols may be used singly or mixtures of two or more of these alcohols may be reacted with phosphorus pentasulde or phosphorus pentoxide and the resulting reaction product reacted with a polyvalent metal or metal oxide to produce Aa. desirable lubricating oil addition agent. Moreover, the ketones listed above may be reduced to the corresponding alcohols and these alcohols may then be employed as above indicated in the production of lubricating oil addition agents.

Hydrocarbons or hydrocarbon fractions such as those specified hereinabove may be oxidized in the liquid phase by blowing or otherwise contacting them'with oxygen, air or other oxygencontaining gaseous mixture. The liquid hydrocarbon is maintained at a temperature and a pressure high enough to cause oxidation to occur. We Ymay oxidize at temperatures in the order of from about 100 F. to about 500 F. although We prefer to carry out the treatment at temperatures in the order of `from about 200 F. to about 350" F. Pressures in the order of from about normal atmospheric io; :ssure to about 300 pounds per square inch gage may be employed, although we prefer to effect the oxidation at gage pressures in the order of from about to about 150 pounds per square inch. The temperature and pressure selected for oxidation will vary with the compound being treated and in general the temperature used will be as low as can be successfully employed to cause the oxidation reaction to proceed at an economical rate. This general rule is followed because it is found that the use of lower temperatures reduces the amount of secondary oxidation products for a given quantity production .of primary oxidation products and also reduces the proportion of oxygenated degradation products and polymerization and/or condensation products. These latter products are defined, for the purpose of this invention, as those products which may contain oxygen or not, which have been produced during the oxidation and which contain fewer carbon atoms per molecule than the hydrocarbon stock being oxidized. Moreover, the pressures employed will vary with the particular hydrocarbon being treated and with the temperature. In general it isdesirable that the pressure be great l enough to prevent the ready volatilization o'f the hydrocarbon stock being oxidized, thus'minlmizing the required condenser and coolerv capacity required .to strip liquid products from the exhaust gasegjeaving the oxidizen f j We may carry out the oxidation without the iid of oxidation catalysts since, in general, liquid phase oxidation of hydrocarbons of the types disclosed hereinabove occurs readily in the'absence of catalysts.l However, we may employ catalysts to increase the rate of oxidation, to permit the use of lower temperatures and/orl pressures which would otherwise be required, or to direct the course of the oxidation reaction. Solid catalysts which are supported in the oxidation vessel are desirable since they do not complicate the separation of partial oxidation products from unoxidized hydrocarbons and are not removed from the oxidation vessel along with portions of the partially oxidized hydrocarbon charge which are withdrawn and treated for the removal of partial oxidation products. Catalysts which-are useful in our process include those oxidation catalysts comprising metals of the series having atomic numbers 20 to 3o, inclusive, i. e., calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc as Well as the metals magnesium, aluminum, molybdenum, silver, tin, tantalum, cerium, neodymium, platinum, thorium, and uranium. By the term oxidation catalysts comprising metals we also intend to include compounds of these metals such as oxides and salts, such as the chlorides, bromides, iodides, nitrates, sulfates, sultes, phosphates, phosphites, Vanadates, titanates, chromates, bichromates, molybdates, tungstates, uranates, etc. These metals, metal oxides or salts maybe used as such or they .may be disports being materials such as pumice, silica gel, koalin, kieselguhr, fullers earth, alumina, magnesia, asbestos ber, etc. Also, combinations of two or more of the above metals, metal oxides, or salts may be used as the catalyst.' In some instances it is desirable to employ a soluble or 'drawn from the bottom of the oxidizer through umn 6, together with its essential appurtenances tended on or impregnated in supports, said suphomogeneous catalyst which would be particulariy active in initiating the oxidation and in such instances an organic salt of the above disclosed metals may be employed. Thus calcium, magnesium, iron, etc., naphthenatesare active oxidation catalysts. Moreover, we may prefer to use an oxidation initiator, such as a peroxide as, for example, benzoyl peroxide, nitrogen peroxide, hydrogen peroxide, etc.

The treatment of a hydrocarbon or hydrocarbon mixture for the production of partial oxidation products is desirably carried out in the equipment illustrated in the drawing. A column 1, consisting of any type of column or vessel suitable for liquid phase oxidation, which if desired, may contain packing material, plates or trays, baffles, or other means of increasing the contact between the hydrocarbon material and the oxygen or oxygen-containing gas and which is arranged for heating and cooling, as by means of steam and Water in internal coils, is maintained at a pressure between about normal atmospheric pressure and 300 pounds per square inch gage. Oxygen, air or other gas containing free oxygen is introduced through valved inlet 2 and exhaust gases and vapors escape'through outlet 3. Partially oxidized hydrocarbon material together with unoxidized hydrocarbon material is withconstitutes the stripping section and this section and its operation 'may be varied as indicated hereinbelow. In those cases in which fractional distillation is employed as the means of effecting the separation of oxygenated molecules, i. e.,

products of partial oxidation, from unoxidizedl hydrocarbon molecules and oxygenated degradation products which boil at temperatures atl or below the boiling point or boiling point range of the hydrocarbon feed. column 6 is maintained at .any desirable pressure between about 29 inches of mercury vacuum and 300 pounds per square inch. gage. In these cases, the products of partial oxidation are removed from the bottom of column B through valved outlet( 8 and the unoxidized hydrocarbon materials, together with degradation products, pass as vapors from the top of the column through line 8 and condenser I 0 where the vapors are condensed and the condensate passes into reux drum II. A portion of this liquid is returned as reflux to the top of column 6 through line I2, the rate oi.y flow through this line being controlled by valve I3. Valved line I4 carries liquid products from reflux drum Il to pump I5 and thence to the oxida- 'tion column I. New feed enters the system through valved line I6 leading into line I4. Ex-4 containing low molecular weight fatty acids, al-

dehydes and other preferentially water-soluble oxygenated products and a hydrocarbon phasey containing in addition tor unoxidlzed hydrocarbons, oxygenat'ed degradation products which are preferentially soluble in the hydrocarbon phase. The aqueous phase is removed through valved outlet 2|. The hydrocarbon phase in separator Isvmay be returned directly to column I through valved outlet 22, or it may be transferred through valved line 23 to a fractionating column 24 which is heated by means of reboiler 25 and operated under atmospheric or higher pressures, in which column the liquid product, separated from the exhaust gases and vapors from the oxidation column, is fractionated to separate as a bottoms fraction, unoxidized liquid hydrocarbons which are returned through line 26 and by means of pump 21 to the oxidation column and as overhead distillate the oxygenated degradation products, said distillate being passed/from the top of column 24 through line 28, condenser 29 and into reux drum 30, A portion of the condensed overhead is returned as reux through line 3| and valve 32 to fractionating column 24. Oxygenated degradation products are produced through line 33 and control valve 34. A valved Y I in the drawing and .described above shows the use l aration, such as those indicated hereinabove.

Thus the fractionating column 6 in the drawing may be used as an extractive distillation column. In such cases, a solvent which preferentially dissolves the oxidized molecules is pumped into the top of the column through valved line 35 and flows downward through the column contacting the vapors ascending the column and' extracting therefrom the partially oxidized hydrocarbon molecules. The solvent, containing the products of partial oxidation, is withdrawn as bottoms from column 6 through valved outlet 8. This mixture is then pumped to a fractionating column (not shown in the drawing) where the partial oxidation products are distilled overhead leaving the solvent as bottoms. The bottoms from this column is returned as solvent to the top of column 6.

Solvents which are useful in segregating the products of partial oxidation from the unoxidized hydrocarbons in the extractive distillation of the mixture of these two components include monohydroxy alcohols, such as ethyl, propyl, isopropyl, and higher molecular weight normal and isomeric alcohols; polyhydroxy alcohols, such as mono, di, tri, tetra-, etc., ethylene glycols; the ethers of these ethylene glycols, such as monomethyl, monoethyl, monobutyl, etc., ethers of mono, di, tri, etc., ethylene glycols; the esters of these ethylene glycols, and the esters of the ethers of ethylene glycols, such as for example, the acetate of the monomethyl ether of ethylene glycol, propylene glycols and the ethers of propylene glycols; the esters of the ethers of propylene glycols, including propylene glycol and dipropylene glycol; polyhydroxy alcohols including the trihydroxy and tetrahydroxy alcohols, such as glycerine and erythritol; hydroxy amines such as ethanolamine, diethanolamine, triethanolamine; halohydrines such as glycolchlorohydrine; amines, such as butylamine, triethylamine and diamines, suchas ethylenediamine; aliphatic ketones, such as methylethyl ketone,

\ diethyl ketone, methylisopropyl ketone, etc., di-

acetyl and acetonyl acetone; cyclic ketones, such as cyclopentanone, cyclohexanone, methylcyclo- ,hexanone and methylphenyl ketone; phenolic compounds, such as phenols, naphthols, cresols, xylenols, thymol, etc.; polyhydric phenols, such as resorcinol, pyrocatechol, pyrogallol, phloroglucinol, etc.; alkylated polyhydric phenols, such as l1-met1fiyl-2, 3-dihydroxy benzene, etc.; saturated tioned nitroparaiins and nitroalcohols, such as chloronitromethane, 1-chloro-1-nitroethane, etc.,

nitro aromatic compounds, such as nitrobenzene,

nitrotoluenes, nitroxylenes, etc.; and alkyl ni 'trites including the normal and isomeric nitrites from butyl to octylnitrite.

The choice of solvent to be employed will generally depend upon the characteristics of the` hydrocarbon stock being oxidized and upon the characteristics of the partial oxidation products being separated since it is preferable that the solver/1t does not form an azeotrope with the unoxidized hydrocarbon stock under the conditions of operation and it is preferable that the solvent have a boiling point at least F. and preferably more than 75 F. above the boiling point of the hydrocarbon stock being treated. It is desirable also thatthe boiling point of the solvent be sufficiently different from the boiling point or boiling point range of' the partial oxidation product that it may be separated therefrom by fractional distillation.

The above disclosed solvents may be used to separate'the products of partial oxidation from the unoxidized hydrocarbon by the well known process of solvent extraction in the liquid phase. Such solvent extraction may be carried out batchwisev or preferably by batch countercurrent or continuous countercurrent extraction. In such processes the oxidized products are dissolved by the solvent and separated as an extract phase which is subsequently fractionally distilled to segregatevthe oxidation products and the solvent, and the unoxidized hydrocarbons or rafiinate phase may be returned to the oxidizer directly or after fractionally distilling or otherwise treating it to remove small quantities of solvent. In addition to the solvents disclosed above we may employ aqueous solutions of mineral acids such as sulfuric acid, -sulfurous acid, nitric acid, hydrochloric acid, phosphoric acid, etc., as the solvents to effect the separation of oxidized products from the unoxidized hydrocarbons. 'I'he addition of about 2 to 4 volumes of water to the aqueous mineral acid solution of alcohols and/or ketones causes the separation of the alcohols and/or ketones as an upper phase which is substantially insoluble in the diluted mineral acid phase and whichmay be decanted from the latter phasel For example, 65% sul- .partial oxidation process.

furie acid is an excellent selective solvent for the primary oxidation products obtained in our We may Vemploy azeotropic distillation to separate the unoxidized hydrocarbons from the products of oxidation using'fractionating column 6 in the drawing as the azeotroping column. This method is desirably employed in those cases in `which the products of oxidation boil at or near the boiling point of the hydrocarbon being oxidized. The compound selected as the azeotrope former forms a minimum boiling point azeotrope with the unoxidized hydrocarbons and thus facilitates the'separation of said hydrocarbons from the oxidation products. Azeotrope formers which may be employed may be selected from the list of solvents disclosed hereinabove for use in extractive distillation processes. In selecting the particular azeotrope former to use in a specic case it is important that the boiling point of the lfractionating column 6 in line 4 in a sumcient quantity to distill overhead all of the unoxidized hydrocarbon together with said azeotrope former leaving the oxidized products as bottoms. substantially free of unoxidized hydrocarbon and azeotrope former. The overhead distillate or azeotrope is withdrawn fromreilex drum Il, through line Il and valved line to an azeotrope former recovery unit where the azeotrope former is separated, as by solvent extraction, from the unoxidized hydrocarbon. The separated unoxidized hydrocarbon is' returned to the oxidizer through valved inlet I6 to line I4, and pump I 5.

We may also use an adsorption process for the removal of partial oxidation products from the mixture of unoxidized and oxidized hydrocarbons withdrawn from the oxidation vessel. In this case the product withdrawn from the oxidizer through. line 4 is contacted with a solid adsorbent, such as activated charcoal, or a mineral adsorbent, such as silica gel, alumina, fullers earth, bentonite, etc., in a percolator. In such a system the oxidized molecules are adsorbed and the unoxidized hydrocarbon after removal of the oxidized products is discharged from the percolator and returned to the oxidizer for further treatment. Two percolators containing an adsorbent are connected in parallel so that one may be used for adsorbing oxidation products while the spent adsorbent in the other percolator is being treated for the recovery of adsorbed products -and otherwise regenerated. 'Regeneration of the spent adsorbent may be accomplished by a steam stripping operation in which steam or superheated steam is blown through the percolator, after first draining all of the unoxidized hydrocarbon from the unit, and the steam containing the oxidation products is condensed and cooled and passed through a separator vessel where the aqueous phase is separated from the oxidation products.

.The crude partialoxidation product, which may be stripped from its mixture with unoxidized hydrocarbon leaving the bottom of the oxidizer by any of the above mentioned processes, consists primarily of molecules having the same number of carbon atoms as the parent hydrocarbon and containing one atom of oxygen. This product comprises alcohols, ketones, or mixtures of alcohols and ketones, which may be produced by a primary oxidation reaction involving only the addition of one atom of oxygen per molecule. Thus, for example, the partial oxidation of methylcyclohexane proceeds in the manner illustrated by the following equations:

ont /H `on\, /on

/G\ /C\ HxC CH: HIC CH:

l 360: B1G Ha En Ha C C Hz Ha Methylcyclohexane l-methylcyclohexanol on, H

/C\ mc om ||y l m E M0; CHz-C-CHs-UHf-CHz-CHz-CE:

\C/ i allontanano Hf Methylcyclohexane In the iirst reaction the oxygen atom enters the molecule at the tertiary carbon atom and the tertiary hydrogen atom attaches itself to the oxyond reaction the oxygen atom replaces the tertiary hydrogen and in this case the ring, breaks at position I, the tertiary hydrogen atom shifting to the end carbon atom of the carbon chain and the reaction results in the formation of an acyclic aliphatic ketone.

Other types of ketones which may be produced by partial oxidation and which may be present in the oxidized product together with the alco- -hols and ketones of the types noted above are the cycloaliphatic ketones. These compounds are produced by the reaction between one molecule of oxygen and one molecule of the hydrocarbon and this type of reaction may be represented by the following equation:

0*( Hs H /C\ /C\ HxC CH: o HxC CH: E o

Ha Hx I Hdl) Hr i C C H: Hz

Cyclohexane Cyolohexanone In .this case one atom of oxygen replaces the two hydrogen atoms attached to one of the car- -bon atoms forming a, cyclic ketone and the thus freed hydrogen atoms combine with the second oxygen atom to form water.

The proportion of alcohol to ketone in a given partial'oxidation product will depend upon the K particular hydrocarbon being oxidized, the catalyst employed, and upon the temperature and pressure maintained in the oxidizer and may therefore be varied Within certain limits by changing the hydrocarbon feed and/or the conditions of treatment. Thus the controlled partial oxidation of methylcyclohexane at relatively low pressures and temperatures results in the production of approximately equal quantities of methylcyclohexanol and 2-heptanon'e, whereas the oxidation of 1,3-dimethylcyclopentane under similar conditions of temperature and. pressure results in the formation of large proportions of 5methylhexanone2 and relatively small proportions of 1,3-dimethylcyclopentanol.

In those instances in which alcohols are the desired products and mixtures of alcohols and ketones are obtained as products of partial oxidation the ketones may be reduced to the corresponding alcohols. This reduction may be carried out on the mixture of alcohols and ketones and in this instance the resulting alcohols would be a mixture of cyclic and acyclic alcohols, or the crude product may iirst be separated into a ketone fraction and an alcohol fraction by fractional distillation or by a chemical .treatment as indicated hereinbelow and the ketone fraction subsequently reduced to the corresponding 9.100-

hol. The reduction may be .carried out by any of the well known processes for reducingl or hydrogenating organic compounds, such as hydrogenation with gaseous hydrogen over a nickel, copper, or platinum catalyst.

This segregation of the partial oxidation products into a fraction consisting primarily of alcohols and a second fraction consisting Aprimarily of ketones may be eiected in any convenient manner. In some instances it is possible to accomplish this separation by fractional distillation. Thus, for example, when oxidizing methylcyclohexane the products of partial oxidation comprise l-methylcyclohexanol which boils at about 315 F, and 2heptanone which boils gen forming a cycloaliphatic alcohol. In the sec-J pressures greater than atmospheric pressure bey cause the vapor pressures of the alcohol and ketone components do not change to the same extent with changes in distillation pressure and thus the spread between the boiling points of the two components usually becomes greater with changes in pressure, often allowing separation of components which boil at the same temperature under ordinary atmospheric pressures.

Chemical methods of separation, wherein a chemical reagent is caused to react, or form an addition compound with one of the components of the mixture, may also be employed. For example, the product of partial oxidation may be washed with a. concentrated aqueous solution of sodium bisulfte which forms an addition product with the ketone. The alcohol which is unaffected by this treatment may then be decanted from the aqueous solution of the ketone addition compound and then decomposed as by warming with alkalis, such as dilute sodium hydroxide or with an acid, such as dilute sulfuric acid, releasing the ketone which may be decanted from the remaining aqueous phase. The alcohol and the ketone may be further puried by fractional distillation.

In those cases in which more than one alcohol and/or more than one ketone is formed by the oxidation reaction, as for example, when the hydrocarbon feed to the oxidizer contains more than one naphthene hydrocarbon, the ketones may be separated from the alcohols, as .indicated above, and the separated components may then be fractionally distilled to separate individual alcohols and/or ketones in those cases in which the boiling points of the individual alcohols and ketones are suiliciently far apart to allow such separation to be made. However, in many instances it is not essential that the alcohol component be separated into individual compounds since mixtures of alcohols such as are produced in our process are entirely satisfactory for most of the uses indicated hereinabove. Moreover, mixtures of ketones of similar' types may be reduced to the corresponding-alcohols and the .thus produced mixture of alcohols may ther separation.

The following specic examples further illustrate the invention.

be employed without furi Example I Methylcyclohexane was pumped into the oxidation column, heated to a temperature of 250 F. and maintained at a pressure of about 90 pounds per square inch gage. Air was introduced at the bottom of the vessel at the rate of 65 cubic feet per barrel of methylcyclohexane per minute for a period of about 20 minutes until analysis of the oxidation charge showed the presence of one atom of combined oxygen per 200 molecules of methylcyclohexane. At this time fresh feed was started into the oxidizer at a rate such that the liquid level in the oxidizer remained constant throughout the operations described below. Partially oxidized methylcyclohexane was removed from the bottom of the column and transferred to a fractionating column maintained at normal atmospheric pressure and a temperature such that the temperature in the vapor line leading from the top of the column was 212.5 F. Unoxidized methylcyclohexane distilled overhead from this fractionating column and was condensed and returned to the oxidizer for further oxidation and oxidized products were removed as bottoms from the fractionating column, said oxidized products being further treated as described hereinbelow. Exhaust gases and vapors leavingthe top of the oxidation column were passed through a condenser and into a separator. The condensed liquid being returned directly to the oxidizer and the uncondensed gases, consisting primarily of spent air, were vented -to the atmosphere.

'I'he oxygenated product obtained as bottoms from the fractionating column consisted primarily of a mixture of equal parts by weight of 1- methylcyclohexanol and 2-heptanone. A portion of\ this mixture was extracted with a saturated aqueous sodium bisulte solution to separate the 2-heptanone, as an addition product with the sodium bisulte, from the l-methylcyclohexanol. The extracted cyclohexanol was subsequently fractionally distilled at reduced pressure to produce a substantially pure 1methylcyclohexanol as a heart cut boiling between 160 F. and 166 F. at 22 mm. of mercury pressure. The bisulfite addition product with the ketone was decomposed by treatment with dilute sulfuric acid, the freed ketone was separated by decantation from the aqueou's layer, washed with additional quantities of water and nally fractionally distilled to produce a heart cut boiling between 300 F. and 304 F. at normal atmospheric pressure and consisting substantially of pure Z-heptanone. 'I'his l latter fraction was reduced to the corresponding alcohol 2-heptanol, by hydrogenation over a nickel catalyst at 300 F. and 400 pounds per square inch pressure for a period of 4 hours. i

A second portion of the oxygenated product obtained as bottoms from the fractionating column and comprising a mixture of 1-methylcyclohexanol and Z-heptanone was hydrogenated in the manner indicated above for hydrogenating the separated Z-heptanone. The product comprised a mixture of l-methylcyclohexanol and 2- heptanol.

To illustrate one use of the alcohols prepared as above, to 457 grams of the l-methylcyclohexanol, the Z-heptanol, or the mixture of these alcohols, is added 222 grams of powdered phosphorus pentasulde and the mixture is agitated and heated to 275 F. for a period of three hours at which time the phosphorus pentasulfide has completely dissolved. To the resulting solution is added 82 grams of zinc oxide and the agitating and heating is continued for an additional four hours at which time the product is filtered hot (275 F.) to remove small amounts of unreacted zinc oxide. This product may be added to an SAE 30 highly solvent refined Western lubricating oil having Saybolt Universal viscosities of 540 seconds at F. and 64 seconds at 210 F. and a Viscosity index (Dean and Davis System) of 90, in the ratio of about 1 part by weight of the zinc salt to 99 parts of the lubricating oll and the resulting mixture heated to about 250 F. and agitated until the zinc salt is dissolved and thoroughly mixed in the oil to produce a lubricating oil composition which is a particularly desirable lubricant for internal combustion engines. wThis lubricating oil composition possesses improved nlm strength, anti-corrosion and detergency 1s of the above mentioned highly'solvent rened Western lubricating oil to produce a lubricating oil composition having high lm strength and anti-"corrosion -characteristics and particularly high detergency characteristics. Example II l A naphthenic fraction of petroleum boiling between 192 F. and 198 F. .prepared by careful fractionation of a straight run gasoline derived from a highly naphthenic crude oil and containing about 50% by volume oi a mixture of l dimethylcyclopentanes was charged to the oxidaby gravity back into the .oxidizer and uncondensed gases were allowed to escape to the atmosphere. The air blowing was continued for a period oi approximately 20 minutes at which time analysis of the liquid in the oxidizer indicated the presence of approximately 0.5% of molecules containing oxygen. At this time fresh feed was pumped into the oxidizer at such a rate that the liquid level in the column remained constant throughout the following operations. The slightly oxidized hydrocarbon fraction was withdrawn from the bottom of the oxidizer and transferred to a fractionating column maintained at normal atmospheric pressure and at a temperature such that the vapor leaving the top of the column had a temperature of 198 F. This overhead vapor consisting of unoxidized hydrocarbon material was condensed, part of the condensate being returned to the fractionating column as reux and part of it being pumped back into the oxidizer along with the new hydrocarbon feed referred to above.

Products of partial oxidation were withdrawn asbottoms from the fractionating column, and transferred to a second fractionating column from which a fraction boiling between about 284 F. and 302 F. was produced as a side cut.

i tated and heated to 275 F. for three hours. To

this product is then added 82 grams of zinc oxide and the heating and agitating continued for an .additional four hours at which time the hot' product is filtered to remove any unreacted zinc oxide. 'I'he resulting zinc salt may be blended v with the lubricating oil described in Example I in the ratio of about 1 part of the zinc salt to 99 parts of the lubricating oil, or 1 part of the zinsalt may-be blended with 1 part of a calcium salt of oil-soluble petroleum sulfonic acids and 98 parts of the same lubricating oil to produce lubricating oil compositions having high film strengths, anti-corrosion and detergency characteristics which are desirable features of lubricants for internal combustion engines and particularly Diesel engines. In each of the above instances the blending may be accomplished by heating to about 250 F. and agitating the ingredients until the added salts are completely dissolved and mixed in the lubricating oil.

This fraction, which amounted to about by volume of the oxidized fraction obtained as bottoms from the -ilrst vfractionating column comprised a mixture of aliphatic ketones having seven carbon atoms per molecule. The overhead from the second fractionating column contained lower boiling alcohols and ketones, i. e., having fewer than seven carbon atoms per molecule, and the bottoms from this column contained a mixture of dimethylcyclopentanols and higher molecular weight alcohols and ketones together with oxygenated polymerization products.

The mixture of aliphatic ketones boiling between about 284 F. and 302 F. lwas reduced to a mixture of the corresponding alcohols by liquid phase hydrogenation with gaseons hydrogen over a nickel catalyst at 300 F. and 400 pounds per square inch gage for a period of four hours. The hydrogenated product was fractionally ,distilled and the mixture of alcohols The foregoing description and examples are not to be taken as in any way limiting but merely illustrative of our invention /for many variations may be made by those skilled in the art without departing from the spirit or scope of the following claims.

We claim:

l. A process for the treatment of a saturated cyclic hydrocarbon to produce substantially only those partial oxidation products containing the same number of carbon atoms per molecule as said saturated cyclic hydrocarbon and containing one atom of oxygen per molecule, comprising contacting said saturated cyclic hydrocarbon in the liquid phase in an oxidation vessel with a gas containing free oxygen at temperatures between about 200 F. and about 350 F. and at pressures between about 50 pounds and about 300 pounds per square inch gage until between about 0.1% and about 10% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said partially oxidized liquid to a fractionating column wherein unoxidized hydrocarbon is vaporized and distilled, withdrawing unvaporized partial oxidation products containing one atom of oxygen per molecule from the bottom of said fractionating column, condensing said vaporized unoxidized hydrocarbon and returning the condensed vaporobtained as a heart cut boiling between about ized unoxidized hydrocarbon together with additional quantities of saturated cyclic hydrocarbon .to said oxidation vessel, passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases are exhausted and returning condensed hydrocarbon from said separator to said oxidation vessel.

2. A process .for the treatment of a saturated cyclic hydrocarbon to produce substantially only those partial oxidation products containing the same number of carbon atoms per molecule as said saturatedv cyclic hydrocarbon and containing one atom of oxygen per molecule, comprising contacting said saturated cyclic hydrocarbon in the liquid phase in an oxidation vessel with a gas containing free oxygen at temperatures between about F. and about 500 F. and at pressures between about 50 pounds and about 300 pounds per square inch gage until between about 0.1% and about 10% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said partially oxidized liquid to a fractionating. column wherein unoxidized hydrocarbon is vaporized and distilled, withdrawing unvaporized partial oxidation products'containing one atom of oxygen per molecule from the bottom of said fractionating column, condensing said vaporizedwunoxidized hydrocarbon and returning the condensed vaporized unoxidized hydrocarbon together with additionalquantities of saturated cyclic hydrocarbon to saidoxidation vessel, passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases are exhausted, passing a condensed hydrocarbon phase from said separator to a fractionating column wherein oxygenated degradation products are4 vaporized and distilled leaving unoxidized hydrocarbon as distillation bottoms and returning said bottoms to said oxidation vessel.

3. A process for the treatment of a naphthene hydrocarbon to produce partial oxidation products containing the same number of carbon atoms per molecule as said naphthene hydrocarbon and containing one atom of oxygen per molecule, comprising contacting said naphthene hydrocarbon in the liquid phase in an 'oxidation vessel with aggas containing free oxygen at temperatures between about 200 F. and about 350 F. and at pressures between about 50 pounds and about 150 pounds per square inch gage until bev tween about 0.1% .and 10.0% of the molecules are oxidized. thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said liquid to a fractionating column in whichunoxidized hydrocarbon is vaporized and distilled and partial oxidation products containing one atom of oxygen per molecule are obtained as distillation bottoms, condensing said vaporized' unoxidized hydrocarbon and returning the condensed vaporized unoxidized hydrocarbon together with a sufficient quantity of said naphthene hydrocarbon to maintain an approximately .constant liquid level in said oxidation vessel, passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases v are exhausted, passing a condensed hydrocar-v bon phase from said separator to a fractionating column wherein oxygenated degradation products are vaporized and distilledI leaving unoxidized hydrocarbon as distillation bottoms and returning said last named distillation bottoms to said oxidation vessel. I

4. A process as in claim 3.wherein said partial oxidation products containing one atom of oxygen per molecule comprise alcohols and ketones containing at least ve carbon atoms per molecule.

5. A process for the treatment of methylcyclohexane to produce l-methylcyclohexanol and 2- heptanone, comprising contacting said methylcyclohexane in the liquid phase inan oxidation vessel with a gas containing free oxygen at temperatures between about 200 F. and about 350 F. and at pressures between about pounds and `150 pounds per square inch gage until between about 0.1% and about 10.0% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said liquid to a fractionating column in which unoxidized methylcyclohexane is vaporized and distilledand from which partial oxidation products comprising l-methylcyclohexanol and 2- and returning the condensed methylcyclohexane together with a sufficient quantityof additional methylcyclohexane feed to maintain an approximately constant liquid level in said oxidation vessel, constantly passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separatorfrom which uncondensed gases are .exhausted and from which condensed hydrocarbon liquid comprising methylcyclohexane is returned tosaid oxidation vessel.

6. A` method of producing l-methylcyclohexanol and Z-heptanoi, comprising contacting/ methylcyclohexane in the liquid phase in an oxidation vessel and in the absence of oxidation catalyst with a gas containing free oxygen at temperatures between about 200 F. and about 350 F. and at pressures between about 50 pounds and pounds persquare inch gage until between about 0.1% and 10.0% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said liquid to a fractionating co1- umn in which unoxidized methylcyclohexane is vaporized and distilled and from which partial oxidation products comprising l-methylcycldhexanol and z-heptanone are obtained as distillation bottoms, condensing said vaporized'methylcyclohexane and returning the condensed methylcyclohexane together with a sufficient quantity of additional methylcyclohexane feed to maintain an approximately constant liquid level in said oxidation vessel, constantly passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases are exhausted and from `which condensed hydrocarbon liquid comprising methylcyclohexane is returned to said oxidation vessel, hydrogenating said partial oxidationn products 'comprising l-methylcyclohexanol and 2heptanone to produce a mixture comprising 1' methylcyclohexanol and 2heptanol.

7. A process as inclaim 6 wherein said partial oxidation product obtained as distillation bottoms comprising 1-methylcyclohexanoland 2- heptanone is separated into a fraction comprising 1methylcyclohexanol and another fraction comprising 2hexanone and said fraction coniprising 2hexanone is hydrogenated'to produce 2- 8. A\process for the 'treatment of dimethylcyclopentane to produce partial oxidation products having at least ve carbon atoms per moleculev and containing one atom of oxygen per molecule comprising contacting said dimethylcyclor pentane in the liquid phase in an oxidation vessel with a gas containing free oXygen at temperatures between about 200 F. and about 350 F. and at pressures between about 50 pounds and 150 pounds per square inch gage until about 0.1% and about 10.0% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said liquid cyclopentane feed to maintain an approximately constant liquid level 1in said oxidation vessel, constantly passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases are exhausted and from which condensed hydrocarbon liquid comprising dimethylcyclopentane is returned to saidoxidation vessel. i

9. A method for the treatment of a dimethylcyclopentane fraction of petroleum boiling be- 'partially oxidized liquid from said oxidation vessel, passing said liquid to a fractionating colunm in which unoxidized dimethylcyclopentane fraction is vaporized and distilled and from which, partial oxidation products comprising ketones and alcohols having seven carbon 'atoms per molecule are obtained as distillation bottoms, condensing said vaporized dimethylcyclopentane fraction and returning the condensate to said oxidation vessel together with a suilicient quantity of additional dimethylcyclopentane fractionv to lmaintain an approximately constant liquid level in said oxidation vessel, constantly passing exhaust gases and vapors from said oxidation vessel through a condenser and into a separator from which uncondensed gases are exhausted and the condensed unoxidized ,dimethy1cyclo pentane fraction is returned' to said oxidation vessel.

10. Aprocess as in claim 9 wherein said ketones are aliphatic ketones.

11. A processas in claim 9 wherein said alcohols are saturated cyclic alcohols.

12. A method for producing aliphatic ketones having seven carbon atoms per molecule comprising airblowing a naphthenic fraction of, petroleum boiling between about 192 F. and 198 F. and containing dimethylcyclopentane in the absence of oxidation catalyst at a. temperature of about 250 F. and at a pressure of about 60 pounds per square inch gage until about 0.1% and 10.0% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules-by withdrawing partially oxidized 1iq uid fromsaid oxidation vessel, passing said liquid to afI iractionating column .in which unoxidized hydrocarbons are vaporized and discondensed hydrocarbons to said oxidation vessel together with a suiclent quantity of said nephthenic fraction of petroleum to me'ntain an approximately constant liquid level in. said oxidation vessel, fractionally distilling! said partial oxidation products obtained as distillation bottoms to separate therefrom a fraction boiling between about 284 F. and about 302 F. comprising said aliphatic ketones having seven carbon atoms per molecule.

13. A method of producing aliphatic alcohols having seven carbon atoms per molecule comprising airblowing a naphthenic fraction of petroleum boiling between about 192 F. and 198 F. and containing dimethylcyclopentane in the absence of oxidation catalyst in an oxidation vessel at a temperature of about 250 F. and a pressure of about pounds per square inch gage until between about 0.1% and 10.0% of the molecules are oxidized, thereafter maintaining said proportion of oxidized molecules by withdrawing partially oxidized liquid from said oxidation vessel, passing said liquid to a fractionating column in which unoxidized hydrocarbons are vaporized and distilled and from which partial oxidation products are obtained as distillation bottoms, condensing said vaporized hydrocarbons and returning the condensed hydrocarbons to said oxidation vessel together with a suiclent'quantity of said naphthenic fraction of petroleum to maintain an approximately constant liquid level in said oxidation vessel, separately fractionally distilling said partial oxidation products obtained as distillation bottoms to separate a fraction boiling between about 284 F. and 302 F. comprising a mixture of aliphatic ketones having seven carbon atoms per molecule hydrogenating said mixture ofraliphatic ketones with gaseous hydrogen at about 300 F. and at a pressure of about 400 pounds per square inch gage in the presence of a nickel catalyst to produce a mixture of alcohols containing -seven carbon atoms per molecule.

ADALBERT FARKAS. ARTHUR F.v STRIBLEY, Ja. 

